Hi! Thanks for the detailed how-to for debugging the IMAP connection.
I ran imapshell and LIST "" "*" returns:
S: * LIST (\HasNoChildren) "/" Calendar
* LIST (\HasChildren) "/" Contacts
* LIST (\HasNoChildren) "/" "Deleted Items"
* LIST (\HasNoChildren) "/" Drafts
* LIST (\Marked \HasNoChildren) "/" INBOX
* LIST (\HasNoChildren) "/" Journal
* LIST (\HasNoChildren) "/" "Junk Email"
* LIST (\HasNoChildren) "/" Notes
* LIST (\HasNoChildren) "/" Outbox
* LIST (\HasNoChildren) "/" "Sent Items"
* LIST (\HasNoChildren) "/" Tasks
Regarding the other issue. The "sent" message was saved to INBOX and never sent.